Optical pulse propagation in resonantly absorbing medium and a new definition of group velocity

光脉冲在共振吸收介质中的传播和群速度的新定义

基本信息

批准号：
14540375
负责人：
TOMITA Makoto
金额：
$ 2.37万
依托单位：
sizuoka university
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2003
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-14540375/
关键词：
pulse propagation group velocity anomalous dispersion superluminal

项目摘要

The purpose of the present research is to establish a new definition of a group velocity : which has a good meaning even in the long pulse propagation distance where the conventional definition of the group velocity breaks down, This new definition takes the effect of the imaginary part of the refractive index into account. The imaginary part, which inevitably exists owing to the Kromas-Kronig relation, is very essential in the pulse propagation in the resonant regions. Chirped pulses show a large Reshaping Delay owing to the spectral shift caused by the imaginary part of the refractive index. In incoherent pulses, there was no way to discuss the pulse velocity. In the present research, we define the position of the incoherent pulses by the centre of gravity, and discussed the meaning of the propagation velocity. While the Reshaping Delay in the individual incoherent pulses appears randomly, this delay is the ensemble averaged and the pulse propagates with a Net Delay.In order to verify the above theoretical predictions, we constructed an experiment system based on a modified Michelson interferometer and a TiO2-Safire laser, and performed systematic experiments on the femtosecond pulse propagation. Form these results, we consider that the new definition of the group velocity has well meaning even in the phase modulated pulses.

本研究的目的是建立一个群速度的新定义：即使在较长的脉冲传播距离中，该速度的常规定义也具有良好的含义，该速度的常规定义分解了，此新定义也考虑到了折射率的假想部分的效果。由于克罗马斯 - 克罗尼格（Kromas-Kronig）的关系而不可避免地存在虚构部分，它在共振区域的脉冲传播中至关重要。由于折射率的假想部分引起的频谱移位，搅动的脉冲显示出较大的重塑延迟。在不连贯的脉冲中，没有办法讨论脉冲速度。在本研究中，我们定义了重心中心不一致的脉冲的位置，并讨论了传播速度的含义。虽然单个不一致的脉冲的重塑延迟似乎是随机的，但这种延迟是平均的，并且脉搏以净延迟进行了延迟。为了验证上述理论预测，我们基于修改的米其顿干涉仪和TIO2-SAFIRE激光和对女性的Tumpersecepatients proumpecatients构建了一个实验系统。形成这些结果，我们认为，即使在相位调制的脉冲中，组速度的新定义也具有很好的含义。